Spray drying, whereby a liquid is transformed into dry powder particles by nebulization of droplets in hot drying air, has been recommended as an alternative to freeze drying for the preparation of inhalation products, as it represents an elegant one-step process for producing biopharmaceutical formulations with unique particle characteristics (see, Ameri M, Maa Y F (2006) Drying Technology 24: 763-768; Maa Y F, Nguyen P A, Swwwney T D, Shire S J, Hsu C C (1999) Pharmaceutical Research 16:249-254; Chen D, Maa Y F, Haynes J (2002) Expert Vaccine Review 1:265-276; and Broadhead J, Rouan S, Rhodes C (1992) Drug Devel. Indust. Pharm 18:1169-1206). Spray drying has the additional advantage of being a faster and more cost-effective dehydration process than freeze drying. Over the past decade, numerous protein delivery technologies have emerged, of which several are powder-based methods—such as microspheres for long-acting delivery, fine powders for pulmonary delivery, and biopharmaceutical/vaccine powders for intradermal delivery (see, Patton, J (1998) Nat Biotechnol 16:141-143; Dilraj A, Cutts F T, de Castro J F, Wheeler J G, Brown D, Roth C, Coovadia H M, Bennett J V (2000) Lancet 355: 798-803; Dilraj A, Sukhoo R, Cutts F T, and Bennett J V (2007) Vaccine 25:4170-4174; Philip V A, Mehta R C, Mazumder M K, DeLuca P P (1997) Int J Phar 151: 165-174; Chan H K, Clark A, Gonda I, Mumenthaler M, Hsu C (1997) Pharm Res 14:431-437; Martonen T, Katz I (1993) J Aerosol Med 6:251-274; Chew N Y K, Bagster D F, Chan H K (2000) Int J Pharm 206:75-83; Broadhead J, Rouan S, Hau I, Rhodes C (1994) J Pharm and Pharm 46:458-467; and Tzannis S T, Prestrelski S J (2000) J Pharm Sci 88:360-370). With the advent of these technologies, efforts to identify appropriate powder formation methods are increasing. It would be advantageous to have a stable powder formulation for viruses used in vaccines whereby the viruses survive spray drying procedures and storage. Also, it would be advantageous to have a stable, spray dried, dry powder formulation of viruses suitable for delivery by inhalation or other routes.